Cements are well known, and inorganic cements, such as Portland Cement, are well known and used to form mortar, concrete, and the like.
A drawback with Portland Cement is its relatively high weight per unit of volume. Another disadvantage with Portland Cement is that it is not suitable to use with fillers which are organic in nature. That is, Portland Cement is more or less limited to use with mineral type fillers. Thus, Portland Cement will not readily bind with fillers containing soils and clays. This means that gravel and sand when used as fillers for Portland Cement must be thoroughly washed and free from salts, humus, clay and certain types of acid.
Another disadvantage with Portland Cement is that the mix water must be clean and free from contamination. Salt water, bore water, brackish water, and water containing a high percentage of other types of salts cannot be used as a mix water with Portland Cement.
Another known type of cement is a magnesium oxychloride cement (Sorel cement) which is a cement used in interior work such as floors in hospitals and public buildings. This cement is made by adding in proper proportions a strong solution of magnesium chloride to magnesia. This cement can be used with organic fillers such as wood flour, cork, and inorganic fillers, such as stones, to provide a set mass in a short period of time which can take a high polish. These oxychloride cements can also use other types of organic fillers such as wood shavings, sawdust and straw.
Disadvantages with magnesium oxychloride cements are their brittleness, porosity and low shelf life. Another disadvantage with this type of cement is that it is not easily handled and is not like Portland Cement which is a dry flowable powder which is relatively easy to handle and use. A further disadvantage is that magnesium oxychloride cements are unstable in water and lose strength on prolonged exposure to water.
Another type of cement is a magnesium oxysulphate cement which is weaker than a magnesium chloride cement, and is obtained by the reaction of magnesium oxide with an aqueous solution of magnesium sulfate. The cements are unstable in water.